Process and apparatus for producing woollike filaments of cellulose hydrate rayon



PROCESS AND APPARATUS FOR PRODUCING WOOLLIKB FILAMENTS OF CELLULOSEHYDRATE RAYON Filed Feb. 6, 1946 Aug. 2, 1949, J. YSTOCKLY ZA'FZQGQPatented Aug. 2, 1949 PROCESS AND APPARATUS FOR PRODUCING WOOLLIKEFILAMENTS F CELLULOSE HYDRATE RAYON Johann Stockly, Zurich, SwitzerlandApplication February 6, 1946, Serial No. 645,941

In Switzerland January 29, 1945 9 Claims. 1

' The present invention relates to a further development of the processand the apparatus de-v scribed in the Swiss Patent No. 233,148.

In the Swiss patent specification No. 233,148 an apparatus for producingwool-like rayon filaments has been disclosed which comprises a filamentpay-out tackle,an impregnating device, a filament feed gear, a dryingtube or duct, a positively driven false-twister, a second filament feedgear, and a reel rigging. Some parts thereof are specially altered. Thetwister, for example, may be constructed in the manner of a ball bearingand comprise an inner rotating portion for the purpose of twisting thefilament, and an outer stationary portion. The said inner portion may berotated, for example, by means of a cord drive. The operation of thisknown apparatus is such that a finished rayon filament, preferably ofthe viscose or copper type, is drawn off the pay-out tackle by the firstfeed gear, and conducted through the impregnating device charged with asuitable impregnating liquid. The filament then passes through thedrying tube, wherein it is given a falsetwist by the subsequent twisteron one hand, and is dried and fixed in twist on the other hand,"iscontinuously drawn forward by the second feed gear, while the twist isundone, and delivered to the .reel rigging. Drying the twisted and, inparticular, suitably pre-impregnated filament then will furnish a yarnstructure of wool-like appearance, stable fri'zzling and great fillingcapacity.

The results attained by means of the known apparatus for producingwool-like frizzle rayon are not quite satisfactory, for, among otherreasons, the operating speed is relatively limited, and since at timesthere appear certain irregularities in the form of fluctuations of thefrizzling intensity in the yarns obtained, the cause of which has notbeen recognised heretofore.

I .have succeeded now in speeding up the operation and in perfecting thetwisting by applying two false-twisters, one ahead of. and one afterthedrying tube, rotating in opposite directions.

From such knowledge there resulted an improved process, comprisingtransferring the wet pre-impregnated filament. from a first twister onto a second twister for false twist and which rotates in the oppositedirections, twisting same, and drying it over this distance withoutbringing any substantial sliding friction to act thereon between the twotwisters.

As has been recognised, the sliding frict on tends to push back thefalse twist on the lilament passing by. Since sliding friction alwaysacts more or less irregularly, the pushing back of the twist also takesplace irregularly, and the deformation is fixed in this irregular formimmediately thereafter. There are many causes for the appearance-ofsliding friction between the two twisters,'the suppression andprevention of which constitute .them'ain object of the presentinvention, amongst which may be mentioned:

' The passage openings, for example, through the drying devices may betoo narrow; the twisters may be'too big or, further. the filament maydescribe too large a cone surface due to the great distance between thepassage aperture of the filament in the rotating portion and the centre,thus rubbing on the passage aperture of the drying device; or the samedrawback may arise because of putting the twister too close to thepassage apertureof the drying device; or, what is more likely, the twotwisters and the inlet and outlet openings. for the filament in thedrying device are not accurately aligned, so that the filament readilyrubs on the walls of the said apertures. I

Preliminaryimpregnation may take place, in a manner known per se, simplyby means of water or aqueous solutions. The swelled and soft filamentthen accommodates itself free of stress into the twisted'shape afterhaving passed through the first twister, and shows a still greatertendency of remaining in the twisted shape after 1 drying. Forpre-impregnating purposes, such solutions may be used at still greateradvantage which contain products of preccndensation orpie-polymerisation or constituents thereof, and

which are capable, upon drying, of forming insoluble products ofcondensation or polymerisation which assist in fixing the filament inthe crimpled form,

formaldehyde condensation products.

An apparatus suited for carrying out the process will be describedhereinafter with reference to the dr'awing and the run of the filament.

In the drawing:

Fig. 1 is "a diagrammatic view of the device according to the invention.

Fig. 2 is a diagrammatic view of a second embodiment of the apparatusaccording to the invention.

The filament I, having been paid out from the supply means 2 ,and havingpassed through the impregnating device 3 and the first filament feedgear 4, is drawn into a first positively driven twister 5. The filamentthen passes through the drying tube 6 into the second twister I, whichsuch as, for example, urealatter rotates in a sense opposite to that ofthe twister 5, and is drawn forward by the feed gear 8 to be finallywound upon the winder 9. The twisters '5, 6 and the inlet and outletapertures i0. I l for the filament in the drying tube 6 are accuratelyaligned and so disposed as to prevent any substantial friction of thefilament between the said twisters.

By disposing two twisters at the points indicated and by the said axialalignment of inlet and outlet and twister centres, the followingadvantages are attained: the false twist need not be applied inside ofthe drying device, and the said twist is kept uniform on the entirepassage through the drying device and may adjust itself, and the twistcannot be pushed back irregularly and in an uncontrolled way and manner,since there are no points of friction. It has been found that thisimprovement is very favourable not only for the intensity but also forthe uniformity of the frizzling to be attained.

Between the two twisters a kind of summation of the twist effect istaking place.

-It has been found advantageous in certain cases to let the two twistersrotate at different speeds, in particularly to have the second twisterrun at a higher speed than the first. In the latter case, the twistafter passing the second twister,

snaps back very lively, which materially favours the filling efiect.

The two twisters, according to the present invention, may be driven bycords l3, H from a common drive shaft i2. By suitably selecting thedrive discs l5, l6 or the twisters themselves, the speed of the lattermay be fixed relatively to each other, i. e. both twisters may be madeto rotate at the same speed, or one faster than the other.

Working with doubled composite filaments to be separated again, whichthen possess a high total titre of 500, 750, 1000 and much more denier,the drying is accomplished even at a still lower speed, and even longerdrying tubes are required.

I have succeeded now in surmounting the said difiiculties, whichparticularly pertain to yarns of high titre, by recognising that one isnot bound to the use of a drying tube or duct when continuously drying afilament twisted intermediate of two twisters rotating in differentdirections, but also may use, without materially impairing the frizzlingefiect, rotating drying devices between the two twisters, wherein thefilament is supported by transport elements at the speed of thedrawn-off filament and without any substantial sliding friction. It thushas been made possible to use filament-transport gears capable ofaccommodating a length of filament of many metres within small space.

For this purpose drying devices comprising continuously operatingfilament-transport gears have proved satisfactory; such as stagger reelsof the kind disclosed in the German patent specifications 236,584,239,822 and 415,479, but also crossed-roller pairs, or fluted-rollerpairs, over which the filament is moved in helical windings when movingthe elements, or finally systems of loose rollers driven solely by thefilament itself. The heating of these rotating filament-transportsystems and of the filament rolling thereon may take place in anysuitable way and manner insofar as the filament is not damaged thereby.It has proved suitable to enclose the filament-transport elements inappropriate casings provided with the suitable inlets and outlets forthe filament and the heating medium respectively. The

' be provided or, additionally, a long drying distance be accommodatedwithin a narrow space, and on the other hand the twisting and frizzlingyet be combined therewith.

There arises the necessity, in many cases, of reserving filamentsections of quite some length, for developing and uncurling the falsetwist between the two twisters, for the long filament section to betwisted; i. e. filament has to be made available for the purpose setforth, ahead of the first and back of the second twister respectively.Further prosecuting the pertinent present idea, it has provedadvantageous, for the purpose of reducing the overall length of theapparatus. to have the filament run over loop-forming rotating rollers,or over idling rollers driven by the filament itself, between the firstfixed point and the iirst twister on one hand, and particularlybetweenthe second fixed point and the second twister on the other hand.

Fig. 2 shows an embodiment of the apparatus according to my presentinvention. The filament l! to be frizzled, made of cellulose hydraterayon, has already been wet impregnated, either on the cone orcontinuously, before reaching the first fixed point in form of the feedgear l8 which comprises a roller pair. The said filament also could havebeen produced from a plurality of filaments by doubling, in which caseit represents a composite filament.- Fig. 2 shows the most importantparts, aside from the filament l1 tobe dressed and the first feed gear I8 designated as first fixed point, viz. the first positively operatingtwister IQ for producing false twist, the subsequent heated dryingdevice 20 with the rotating filamenttransport rigging 2 I, the secondtwister 22 rotating in a sense opposite to that of the first twister,the loop-forming filament-reversing rollers 23, and the second feed gear24 as second fixed point. Not shown are: the impregnating device, anypossible doubling and separating tackles required when working with acomposite filament, as well as the pay-out and take-up reel riggings.

The filament-transport gear 2| within the drying device 20 may beadapted in accordance with any of. the embodiments described or similarthereto.

What I claim and desire to secure by Letters Patent is:

1. In apparatus for applying a frizzle to cellulose filaments, afilament drying device, two positively operating false-twisters one ahead ofand one following the drying device, and means for rotating saidtwisters in opposite directions, aid rotating means including a commondrive shaft and cords engaging the respective twisters, said apparatusbeing free of any stationary structural parts in position to exert anysubstantial friction on a filament extending through said twisters anddrying device.

2. In apparatus for applying a frizzle to cellulose filaments, afilament drying device including a heated rotating filament transportdevice capable of accommodating a substantial length of filament in aplurality of loops or windings, two positively operating false-twistersone ahead of and one following the drying device, and means for rotatingsaid twisters in opposite directions, said apparatus being free of anystationary structural parts in position to exert any substantialfriction on a filament extending through said twisters and dryingdevice.

3. In apparatus for applying a frizzle to cellulose filaments, afilament drying device including a heated rotating filament transportdevice capable of accommodating a substantial length of the filament inthe form of loops and windings, two positively operating false-twistersone ahead of and one following the drying device, and means for rotatingsaid twisters in opposite directions, and loop-forming filament-guiderollers disposed after'the second of said twisters, said apparatus beingfree of any stationary structural parts in position to exert anysubstantial friction on a filament extendin through said twisters anddrying device.

4. A process of producing wool-like rayon filaments of the cellulosehydrate type, comprising impregnating a, filament with a liquid torender the filament soft and drying the filament while being highlytwisted by means of two positively operating false-twisting devices oneahead of and one following the drying device, the filament passingbetween the two twisters being out of contact with any member or part ofthe drying device.

5. In apparatus for producing wool-like rayon filaments ofthe cellulosehydrate type, a filament drying device, two positively operatingfalsetwisters one ahead of and one following the drying device, thearrangement being such that the filament between the two twisters is outof contact with any member or part of the drying device.

6. In apparatus for producing wool-like rayon filaments of the cellulosehydrate type, a filament drying device, two positively operatingfalsetwisters one ahead of and one following the drying device, andmeans for rotating said twisters in opposite directions, said rotatingmeans including a common drive shaft and cords engaging the respectivetwisters, the arrangement being such that the filament between the twotwisters is out of contact with any member or part of the drying device.

7. In apparatus for producing wool-like rayon o filaments ofthe'cellulose hydrate type,a filament drying device including a heatedrotating filament transport device capable of accommodating asubstantial length of filament in a plurality of loops or windings, twopositively operating falsetwisters one ahead of and one following thedrying device, and means for rotating said twisters in oppositedirections, the arrangement being such that the filament between the twotwisters is out of contact with any member or part of the drying device.

8. In apparatus producing wool-like rayon filaments of the cellulosehydrate type, a filament drying device including a heated rotatingfilament transport device capable of accommodating a substantial lengthof the filament in the form of loops or windings, two positivelyoperating falsetwisters one ahead of and one following the dryingdevice, and means for rotating said twisters in opposite directions, andloop-forming filamentguide rollers disposed after the second of saidtwisters, the arrangement being such that the filament between the twotwisters is out of contact with any member or part of the drying device.

9. In apparatus for producing wool-like rayon filaments of the cellulosehydrate type, a filament drying device including a heated rotatingfilament transport device capable of accommodating a substantial lengthof the filament, two positively operating false-twisters one ahead ofand one following the drying device, and means for rotating saidtwisters in opposite directions, and loop-forming filament-guiderollersdisposed after the second of said twisters, the arrangement being suchthat the filament between the two twisters is out of contact with anymember or part of the drying device.

JOHANN STOCKLY.

REFERENCES crrEn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 777,696 Rhodes Dec. 20, 19042,089,198 Finlayson et al. Aug. 10, 1937 2,089,239 Whitehead Aug. 10,1937 2,363,871 Keen et al. Nov. 28, 1944

